Microwave ablation (MWA) is a medical procedure where in vivo tissue is ablated using high frequency electromagnetic field to treat a medical disorder. MWA is commonly performed to treat tumors in body organs. During MWA, a needle-like MWA probe is placed inside the tumor. Microwaves emitted from the probe heat surrounding tumor tissue, destroying the target tissues, such as soft tissue, cancerous tumor, nerve, or other target structure. Cancer cells, in particular, break down and die at elevated temperatures caused by MWA procedures. Some MWA procedures create temperatures up to or exceeding 300 degrees Celsius.
For MWA to be successful, a sufficient amount of molecular agitation must occur within the tissue. For example, the varying electromagnetic field generated by the waves emitted from the MWA probe causes water molecules to rapidly vibrate as they attempt to align with the varying field. This molecular agitation creates frictional heat which is capable of rapidly increasing the temperature of the tissue in a similar manner as a microwave oven heats food.
It is desirable to heat the entire area of the tumor with a single treatment. However, it is difficult to obtain even heat distribution using current ablation techniques. When heated to above 60° C., tissue will immediately coagulate.